Group 7 element
From Academic Kids
All of these elements are classed in Group 7 because their valence shell holds four electrons. Technetium has no stable isotopes. Technetium, and promethium (61), are the only two such elements before polonium, after which no known element has a stable isotope.
|Key to color coding in table slice on right:||Transition metals|
Color coding for these atomic numbers: At room temperature, all are solid; red indicates item is synthetic and does not occur naturally.ca:Grup 7 de la taula perịdica es:Elementos del grupo 7 it:Elementi del gruppo 7